Hydraulic presses for the stamping of domed metal sheets, e.g. in the formation of automotive-vehicle body parts, are known in which an upper beam is movable by a piston-and-cylinder arrangement relative to a lower beam to which the piston-and-cylinder arrangement, hereinafter hydraulic cylinder, is connected. The piston rods of the hydraulic cylinders constitute the columns of the press.
In this conventional construction, the piston rods carry an upper beam which is releasably mounted upon these rods by means of anchoring nuts. In order to permit the columns to take up the bending moment imparted to the upper beam during the pressing process, the cylinders which receive the piston rods are generally mounted on the lower beam and between these cylinders and the piston rods, a pivotal connection is provided. At their upper ends, the piston rods are provided with axial-elastic annular compression sleeves engaged by anchor nuts to provide a somewhat pivotal connection between the piston rods and the upper beam. Each of the axial-elastic pressure sleeves is formed as a profiled sleeve and is centered in an annular recess filled with elastic material in a support ring bearing upon the upper beam. The piston rod has a threaded end which passes through the profiled sleeve and the pressure-transmitting ring and threadedly receives the anchor nut.
The pivotal connection of the piston rod in the cylinder is effected usually by a floating disk which bears against a nut threaded onto the cylinder whereby the inner surface of the disk and the portions of the piston engaging the cylinder wall have rounded configurations.
As a consequence of this construction, in this conventional press the pivot permitting canting of the upper beam is excessively complex since either the axial-elastic pressure sleeve or the floating disk may be readily damaged upon the development of extremely high pressing forces and relatively large bending moments (cf. German patent DT-PS 1,962,811).